Stuart Allman <studio@HALCYON.COM> wrote:

> What is the fastest floating point square root algorithm?

Stuart:

That's a lot like asking, "Who's the best-looking woman?" or "What's
the fastest car?"

The choice of an algorithm depends on your particular application
and how you define "fast"; a flip response to your question is, "A
lookup table," but constructing a large-enough one for all 24-bit
floating-point inputs is about as practical as (getting back to the
car analogy) building a car with top-fuel dragster acceleration,
Formula-1 handling, and Bonneville top speed...  Not likely.

What's the range of inputs to your square-root function?  What sort
of precision do the outputs need?  How much code/data space are you
willing to trade for speed?  Is it possible that you can solve your
problem without doing square roots at all?

-Andy

Andrew Warren - fastfwd@ix.netcom.com
Fast Forward Engineering, Vista, California
http://www.geopages.com/SiliconValley/2499